Process for preparing nuclear-fluorinated aromatics

ABSTRACT

The present invention relates to the preparation of nuclear-fluorinated aromatics by reacting, with a fluoride at 40 to 260° C., an aromatic compound substituted at the nucleus with halogen that is exchangeable for fluorine in the presence of at least one compound of the formula (I) 
                         
where A, B, and Any have the meanings specified in the disclosure.

BACKGROUND OF THE INVENTION

The present invention relates to an improved process for preparingnuclear-fluorinated aromatics by a halogen exchange reaction (halexreaction) in the presence of a catalyst.

Nuclear-fluorinated aromatics are important intermediates for preparingbiologically active substances for pharmaceutical and agrochemicalapplications.

It is known to carry out halex reactions in aprotic, strongly polarsolvents using metal fluorides at elevated temperature and in thepresence of alkylammonium or alkylphosphonium salts (U.S. Pat. No.4,287,374), pyridinium salts (WO 87/04149), crown ethers (DE-A 197 02282), or tetraamidophosphonium salts (WO 98/05610). Disadvantages inreactions of this type are, particularly when weakly activated aromaticsare used, the high reaction temperatures and long reaction times thatare required. This leads to high energy consumption and low space-timeyields. The high reaction temperatures frequently lead to the formationof unwanted by-products and decomposition products. In addition largeamounts of expensive solvents are required.

Furthermore, for example, the tetraamidophosphonium salts (WO 98/05610)are extremely toxic.

The requirement therefore still exists for a process for preparingnuclear-fluorinated aromatics by a halex reaction in which less energyis consumed, higher chemical and space-time yields are possible, andsolvents may optionally be avoided.

SUMMARY OF THE INVENTION

A process has now been found for preparing nuclear-fluorinated aromaticscomprising reacting, at 40 to 260° C.,

-   (1) an aromatic compound substituted at the nucleus with halogen    that is exchangeable for fluorine,    with-   (2) a fluoride,    in the presence of-   (3) at least one compound of the formula (I),

where

-   -   A is a radical of the formula (II) or (III)        —P(NR¹R¹)₃

(III)

-   -   and    -   B independently of A is a radical of the formula (II), (III),        (IV), or (IVa)

—S(NR¹R¹)₂  (IVa),

-   -   where the individual R¹ are identical or different and are each        unbranched or branched C₁–C₁₀ alkyl, unbranched or branched        C₂–C₁₀ alkylene, or C₆–C₁₂ aryl,    -   where one or more NR¹ R¹ groups can also be a 3- to 7-membered        saturated or unsaturated ring that is formed from the nitrogen        atom, the remainder of the ring atoms being carbon atoms, and    -   where the radical of the formula (II) and the

-   -    group in formula (IV) can also be the radical of a saturated or        unsaturated 4- to 8-membered ring that contains the two nitrogen        atoms, the remainder of the ring atoms being carbon atoms,        X is nitrogen or phosphorus, and        An^(⊖) is one equivalent of an anion.

DETAILED DESCRIPTION OF THE INVENTION

Preferably, the two R¹ radicals bound to the same nitrogen atom areidentical.

Preferably, the radicals R¹ are methyl, ethyl, propyl, or butyl, or anNR¹ R¹ group is a 5- to 7-membered saturated or unsaturated ring that isformed from one nitrogen atom, the remainder of the ring atoms beingcarbon atoms, or the radical of formula (II) or the

group in formula (IV) is a saturated 5- or 7-membered ring that containsthe two nitrogen atoms, the remainder of the ring atoms being carbonatoms; X is nitrogen; and An^(⊖) is chloride, bromide, (CH₃)₃SiF₂ ^(⊖)),HF₂ ^(⊖)), H₂F₂ ^(⊖)), tetrafluoroborate, hexafluorophosphate,carbonate, or sulfate.

Very particularly preferred compounds of the formula (I) are thosecorresponding to the formulas (V) to (IX).

It is an advantage of the inventive process that it can be applied to agreat number of aromatic compounds substituted with halogen that isexchangeable for fluorine, and thus a great number ofnuclear-fluorinated aromatics can be prepared. The halogen that isexchangeable for fluorine can be, for example, chlorine and/or bromine.Preference is given here to chlorine.

For example, using the inventive process, advantageously,nuclear-fluorinated aromatics of the formula (X) can be preparedR² _(x)ArF_(w)Cl_((y-w))R_(Z) ³  (X),where

-   R² independently of one another are each F, Cl, Br, NO₂, CN, CF₃,    CCl₃, CHO, OCF₃, SCF₃, COR⁴, COOR⁴, COY, or SO₂Y, where R⁴ is C₁–C₁₀    alkyl and Y=F, Cl, Br or CF₃,-   R³ independently of one another are each hydrogen or an unbranched    or branched C₁–C₁₀ alkyl or C₁–C₁₀ alkoxy radical,-   Ar is an aromatic or heteroaromatic radical having a total of 6 to    10 ring atoms, where the ring atoms are only carbon atoms or    alternatively are carbon atoms plus 1 to 3 heteroatoms selected from    the group consisting of nitrogen, oxygen, and sulfur,-   x is an integer from 1 to 3,-   w is an integer from 1 to y,-   y is an integer from 1 to 5, and-   z is zero or an integer from 1 to 5, where the total x+y+z equals    the number of all substitutable valencies on the radical Ar.

Preferably, suitable aromatic compounds substituted with halogen that isexchangeable for fluorine are those corresponding to the formula (XI)R² _(x)ArCl_(y)R³ _(z)  (XI),where R², R³, Ar, x, y, and z have the meanings specified for formula(X).

Preferably, in the formulas (X) and (XI)

-   R² independently of one another are each Cl, NO₂, CN, CF₃, COCl, or    CHO,-   R³ independently of one another are each hydrogen, methyl, ethyl,    methoxy, or ethoxy,-   Ar is a phenyl or pyridyl radical,-   x is 1 or 2,-   w is 1 or 2,-   y is an integer from 1 to 4, and-   z is zero or 1.

Examples of compounds of the formula (XI) are2,3,4,5-tetrachloro-benzotrifluoride, 4-chloronitrobenzene,3,4-dichlorobenzonitrile, 2,6-di-chlorobenzonitrile,2,4-dichlorobenzaldehyde, 3,4,5-trichloropyridine, 4-chlorobenzaldehyde,3,4-dichlorobenzotrifluoride, 1,2,3-trichlorobenzene and2,6-dichlorobenzoyl chloride.

Fluorides that are suitable for an exchange of halogen for fluorine are,for example, alkali metal fluorides, alkaline earth metal fluorides, andammonium fluorides. Preference is given to potassium fluoride, sodiumfluoride, calcium fluoride, and ammonium fluoride and mixtures thereofamong one another and mixtures thereof with lithium fluoride, rubidiumfluoride, and/or cesium fluoride.

Based on 1 mol of halogen that is bound to the nucleus of an aromaticcompound and is to be exchanged for fluorine, for example, 0.001 to 0.5mol (preferably 0.01 to 0.02 mol) of one or more compounds of theformula (I) and, for example, 0.8 to 2 equivalents (preferably 1.1 to1.3 equivalents) of one or more fluorides can be used.

The inventive process is preferably carried out at temperatures in therange 70 to 220° C. Particular preference is given to 90 to 200° C.

The inventive process can be carried out in the presence or absence ofsolvents. Particularly for the conversion of polychlorinatedbenzotrifluorides to fluorinated and chlorinated benzotrifluoridesand/or to polyfluorinated benzotrifluorides, a solvent is not necessary.If it is wished to use a solvent, dipolar aprotic and nonpolar aproticsolvents, for example, are suitable. Suitable dipolar aprotic solventsare, for example, dimethyl sulfoxide, sulfolane, dimethylformamide,dimethylacetamide, 1,3-dimethylimidazolin-2-one, N-methylpyrrolidone,acetonitrile, and benzonitrile. Suitable nonpolar aprotic solvents are,for example, benzene, toluene, chlorobenzene, dichlorobenzenes,chlorotoluenes, and chloro-alkanes such as dichloromethane.

Nonpolar aprotic and dipolar aprotic solvents can be used in anyamounts, for example, in amounts of 0.1 to 500% by weight (preferably inamounts of 0.2 to 40% by weight), in each case based on the aromaticcompound that is substituted with halogen exchangeable for fluorine.

Mixtures of solvents can also be used, in which case it is preferred touse those solvent mixtures that contain 50% by weight or more of dipolaraprotic solvents.

The reaction time in the inventive process can be, for example, in therange of from 2 to 36 hours.

The inventive process can be carried out under reduced, atmospheric, orelevated pressure. Preferably, atmospheric pressure or slightly elevatedpressure (for example, 1 to 6 bar) is employed.

In principle, the compounds of formula (I) can be handled in thepresence or absence of atmospheric oxygen. However, it is preferred tohandle the compounds of the formula (I) under protective gas and tocarry out the inventive process under protective gas. Suitableprotective gases are, for example, nitrogen and argon.

The inventive process may be carried out batchwise or continuously.

To work up the reaction mixture that is present after carrying out theinventive process, a procedure can be followed, for example, in such amanner that the reaction mixture, after cooling, is mixed with water,the organic phase that forms is separated off, and the separated organicphase is subjected to fractional distillation at reduced pressure. Thereaction mixture that is present after carrying out the inventiveprocess can also be subjected directly to distillation.

In addition, a solvent can be added to the reaction mixture, solidconstituents can be separated off by filtration, and the filtrate can bedistilled under reduced pressure. It is also possible to employ otherworkup methods.

The compounds of the formula (I) in which A and B are identical and eachcorrespond to a radical of the formulas (II) or (III) can be prepared ina known manner or by similar methods thereto (see Synthesis 1979,215–216, and Angewandte Chemie, 104, 864, 1992)).

The present invention also relates to a process for preparing any of thecompounds of the formula (I) comprising

-   (a) reacting    -   (i) a compound of the formula        [A-An′]^(⊕)An^(⊖)  (XII),        -   where        -   A has the meaning specified for formula (I) or corresponds            to the formula (IVa),            -   An′ is chlorine or bromine, and            -   An^(⊖) is one equivalent of an anion,    -   with    -   (ii) a compound of the formula (XIII)        HN=A′  (XIII),    -   where    -   A′ with respect to the arrangement of the atoms has the meaning        specified for A of formula (I) but is double-bonded, and-   (2) adding a base.    An example of such a reaction is

In the formulas (XII) and (XIII), A and An^(⊖) preferably have themeanings specified as preferred for formula (I), An′ is chlorine orbromine, and A′ has the preferred meaning specified for A for formula(I) but is double-bonded.

Suitable bases are, for example, alkoxides, tertiary amines, andcompounds of the formula (XIII) used in excess. Preference is given tosodium alkoxides and potassium alkoxides of unbranched or branched C₁–C₄alkyl alcohols and tri(C₁–C₁₀ alkyl)amines. Particular preference isgiven to sodium methoxide, sodium ethoxide, and triethylamine. Ifcompounds of the formula (XIII) are available fairly inexpensively (forexample, if this is the case for tetraalkylguanidine), then excesses ofcompounds of the formula (XIII) as bases are also particularlypreferred.

Compounds of the formula (XII) can be prepared in a known manner or in asimilar manner thereto, for example, by halogenating the correspondingurea, for example, using SOCl₂, (COCl)₂ or COCl₂, or by reactingphosphorus pentachloride with a secondary amine such as diethylamine, orby halogenating a compound of the type (R₂N)₂S with, for example,bromine.

Compounds of the formula (XIII) can be prepared in a known manner orusing similar methods thereto, for example, by reacting phosphoruspentachloride with a secondary amine, ammonia, and an alkali metalhydroxide solution, for example, according to the following equation:

The compounds of the formula (XIII) can also be used in the form oftheir hydrohalides, as frequently first occur during their preparation.

In the inventive process for preparing compounds of the formula (I), acompound of the formula (XIII) can be used, for example, in an amount of0.8 to 3 mol (preferably 1 to 2 mol), based on the compound of theformula (XII).

The compounds of the formulas (XII) and (XIII) can be reacted, forexample, at temperatures in the range −80 to +70° C., preferably in therange −70 to +20° C. Within these temperature ranges it is advantageousto employ relatively high temperatures for the formation of N—C bonds,medium temperatures for the formation of N—P bonds, and relatively lowtemperatures for the formation of N—S bonds.

Suitable solvents are, for example, chlorinated aliphatic and aromatichydrocarbons, ethers, in particular cyclic ethers, nitrites, amides,sulfoxides, and aliphatic and aromatic hydrocarbons. Preference is givento methylene chloride, 1,2-dichloroethane, tetrahydrofuran, dioxane,toluene, acetonitrile, dimethylformamide, and dimethyl sulfoxide. Caremust be taken in selection of the solvent so that it does not convertinto the solid state under the reaction conditions.

The reaction of a compound of the formula (XII) with a compound of theformula (XIII) is generally complete after 0.5 to 24 hours, frequentlyafter 4 to 12 hours. Then, the base can be added, for example, in anamount of 1 to 1.2 equivalents, based on one mole of the compound (XII).When, as base, an excess of compound (XIII) is used, then, for example,in total 2 to 2.2 mol of the compound of the formula (XIII), based onthe compound (XII), can be used. Suitable solvents for alkoxides andtertiary amines are particularly alcohols. Excess compounds of theformula (XIII) do not require additional solvent. The base can be added,for example, at −50 to +40° C., preferably at −10 to +10° C. It isadvantageous to stir the reaction mixture further after completion ofthe addition of base for some time (for example, 0.5 to 1 hour) in thespecified temperature range.

To work up the reaction mixture, for example, after removing the solidconstituents, solvent can be taken off and the product then present canbe purified for example by extraction with a solvent, for example, aketone, ether, or hydrocarbon. Other potential workup methods are alsoconceivable.

It is advantageous to carry out the synthesis and workup of compounds ofthe formula (I) under a protective gas atmosphere, for example, undernitrogen or argon.

The compounds of the formula (I) prepared according to the invention aresuitable for use as catalyst for halex reactions as they are obtainedafter the above-described workup. In some cases it has been observedthat, in the inventive preparation of compounds of the formula (I),mixtures of two or more individual compounds corresponding to theformula (I) are produced. Such mixtures of substances are also suitableas catalysts for halex reactions. These mixtures of substances can be,for example, those containing compounds of the formula (I) where A isformula (II) and B is formula (IV) and formula (IVa) or the compounds ofthe formula (I) where A is formula (III) and B is formula (IV) andformula (IVa). The inventive process for preparing compounds of theformula (I) below provides a universally applicable process by whichcompounds of the formula (I) are accessible in a simple and efficientmanner.

The invention further relates to compounds of the formula (I)

where

-   A is a radical of the formula (II) or (III)

and

-   B independently of A is a radical of the formula (IV) or (IVa)

—S(NR¹R¹)₂  (IVa),

-   -   where the individual R¹ are identical or different and are each        an unbranched or branched C₁–C₁₀ alkyl, unbranched or branched        C₂–C₁₀ alkylene, or C₆–C₁₂ aryl,    -   where one or more NR¹ R¹ groups can also be a 3- to 7-membered,        saturated or unsaturated ring that is formed from one nitrogen        atom, the remainder of the ring atoms being carbon atoms, and    -   where the radical of the formula (II) and the

-   -    group in formula (IV) can also be the radical of a saturated or        unsaturated 4- to 8-membered ring that contains two nitrogen        atoms, the remainder of the ring atoms being carbon atoms,

-   X is nitrogen or phosphorus, and

-   An^(⊖) is one equivalent of an anion.

Preferably the radicals R¹ are methyl, ethyl, propyl, or butyl, or anNR¹ R¹ group is a 5- to 7-membered saturated or unsaturated ring that isformed from one nitrogen atom, the remainder of the ring atoms beingcarbon atoms, or the radical of the formula (II) or the

group in formula (IV) is a saturated 5- or 7-membered ring that containstwo nitrogen atoms, the remainder of the ring atoms being carbon atoms;X is nitrogen; and An^(⊖) is chloride, bromide, (CH₃)₃SiF₂ ^(⊖), HF₂^(⊖), H₂F₂ ^(⊖), tetrafluoroborate, hexafluorophosphate, carbonate, orsulfate.

Particular preference is given todiethylaminobis(tetramethyl-guanidino)sulfonium bromide [formula (VII)]and diethylaminobis[tris-(diethylamino)phosphazenyl]sulfonium bromide[formula (VIII)].

These inventive compounds are accessible, as described, via theinventive preparation process.

The inventive process for preparing nuclear-fluorinated aromatics usesmore effective catalysts, requires less energy, makes possible higherchemical and space-time yields, and can if appropriate be carried outwithout addition of solvent. Frequently, in this inventive process,fewer toxic compounds must be handled than in the process of the priorart. Even if, in a specific individual case, only one or two of theseadvantages should be realizable, this is a considerably improved processcompared with the prior art.

The following examples further illustrate details for the process ofthis invention. The invention, which is set forth in the foregoingdisclosure, is not to be limited either in spirit or scope by theseexamples. Those skilled in the art will readily understand that knownvariations of the conditions of the following procedures can be used.Unless otherwise noted, all temperatures are degrees Celsius and allpercentages are percentages by weight.

EXAMPLES Example 1 Inventive Preparation of 4-nitrofluorobenzene

157 g of 4-nitrochlorobenzene, 200 g of dimethylsulfoxide, 62.7 g ofpotassium fluoride, and 2.49 g of(N,N-dimethylimidazolidino)tetramethyl-guanidinium chloride were placedin a 1 liter four-neck flask equipped with thermometer, anchor stirrer,and reflux condenser with bubble counter. The mixture was heated withstirring to 170° C. and kept at this temperature for 5 hours. Thereaction mixture was then cooled to room temperature, water was added ata volumetric ratio of 1:1, the phases that formed were separated, and,from the organic phase, by fractional distillation at reduced pressure,4-nitrofluorobenzene was obtained in a yield of 96% of theory.

Comparative Example 1 Preparation of 4-nitrofluorobenzene According tothe Prior Art

A procedure was followed as in Example 1, but instead of(N,N-dimethylimidazolidino)tetramethylguanidinium chloride, the samemolar amount of tetrakis(diethylamino)phosphonium bromide was used.4-Nitrofluorobenzene was obtained after a 6-hour reaction time in ayield of 93% of theory.

Comparative Example 2 Preparation of 4-nitrofluorobenzene According tothe Prior Art

A procedure was followed as in Example 1, but instead of(N,N-dimethylimidazolidino)tetramethylguanidinium chloride, the samemolar amount of tetraphenylphosphonium bromide was added.4-Nitro-fluorobenzene was obtained after a 6-hour reaction time in ayield of 89% of theory.

Example 2 Inventive Preparation of 3-chloro-4-fluorobenzonitrile

172 g of 3,4-dichlorobenzonitrile, 200 g of dimethylsulfoxide, 69.6 g ofpotassium fluoride, and 3.95 g of(N,N-dimethylimidazolidino)tris-(diethylamino)phosphazenium chloridewere placed in a 1 liter four-neck flask equipped with anchor stirrer,thermometer, and reflux condenser with bubble counter. The mixture wasthen heated with stirring to 170° C. and this temperature was maintainedfor 6 hours. The mixture was then cooled to room temperature, water wasadded to the reaction mixture in a volumetric ratio of 1:1, and the3-chloro-4-fluorobenzonitrile that precipitated was isolated byfiltration, washing, and drying. 3-Chloro-4-fluorobenzo-nitrile wasobtained in a yield of 92% of theory.

Comparative Example 3 Preparation of 3-chloro-4-fluorobenzonitrileAccording to the Prior Art

The procedure was followed as in Example 2, but the catalyst was anequivalent molar amount of tetraphenylphosphonium bromide.3-Chloro-4-fluorobenzonitrile was obtained in a yield of 81% of theory.

Example 3 Inventive Preparation of 4-fluorobenzonitrile

200 g of 4-chlorobenzonitrile, 101.4 g of potassium fluoride, 25 g ofdimethyl sulfoxide, and 5.60 g of(N,N-dimethylimidazolidino)tetramethyl-guanidinium chloride were placedin a 1 liter 4-neck flask equipped with anchor stirrer, thermometer, andreflux condenser with bubble counter. The mixture was then heated withstirring to 180° C. and this temperature was maintained for 16 hours.The mixture was then cooled to room temperature, water was added to thereaction mixture in a volumetric ratio of 1:1, and the mixture wasextracted with diethyl ether. After washing, concentration, and dryingthe separated organic phase, 4-fluorobenzo-nitrile was isolated in ayield of 75%.

Comparative Example 4 Preparation of 4-fluorobenzonitrile According tothe Prior Art

25.3 g of potassium fluoride in 70 ml of sulfolane were placed in a 250ml 4-neck flask equipped with anchor stirrer, thermometer, and refluxcondenser with bubble counter, and the mixture was stirred for 1 hour at100° C. The reflux condenser was then removed, a distillation head wasattached instead, and 20 ml of sulfolane were distilled off underreduced pressure. The apparatus was then charged with nitrogen, thereflux condenser was again attached, and 50 g of 4-chlorobenzonitrileand 1.52 g of tetraphenylphosphonium bromide were added. The mixture wasthen heated with stirring to 180° C. and this temperature was maintainedfor 6 hours. It was then found by gas-chromatographic analysis that only2% of the 4-chlorobenzonitrile used had been converted to4-fluorobenzo-nitrile.

Example 4 Inventive Preparation of 2,4-difluorobenzoyl Fluoride

100 g of 2,4-dichlorobenzoyl chloride, 100 g ofN,N-dimethylimidazolidin-2-one, 94.3 g of potassium fluoride, and 1.78 gof (N,N-dimethylimidazolidino)tetramethylguanidinium chloride wereplaced in a 1 liter 4-neck flask equipped with anchor stirrer,thermometer, and reflux condenser with bubble counter. The mixture wasthen heated with stirring to 180° C. and this temperature was maintainedfor 24 hours. The mixture was then cooled to room temperature,dichloromethane was added to the reaction mixture in a volumetric ratioof 1:1, and the mixture was filtered. The solvent was removed from thefiltrate and the remainder was subjected to fractional distillation.2,4-Difluorobenzoyl fluoride was obtained in 75% yield.

Comparative Example 5 Preparation of 2,4-difluorobenzoyl FluorideAccording to the Prior Art

200 g of 2,4-chlorobenzoyl chloride and 200 g of sulfolane were placedin an autoclave and heated for 9 hours with stirring at 200° C. Themixture was then allowed to cool to room temperature and depressurizedand the product was distilled off directly from the reaction mixture. Inthis manner 2,4-difluorobenzoyl fluoride was obtained in 35% yield.

Example 5 Inventive Preparation of Tetrafluorobenzotrifluoride

(a) 400 g of tetrachlorobenzotrifluoride, 212 g of potassium fluoride, 5g of (N,N-dimethylimidazolidino)tetramethylguanidinium chloride, and 2 gof dichloromethane were placed in a 1 liter autoclave and heated withstirring for 8 hours at 200° C. The mixture was then cooled to roomtemperature, the precipitated salts were filtered off, and the filtratewas analyzed by gas chromatography. The analytical results can be seenin Table 1.(b) The filtrate from substep (a) was placed in a 1 liter autoclavetogether with 6.3 g of (N,N-dimethylimidazolidino)tetramethylguanidiniumchloride and 193.5 g of potassium fluoride and heated for 32 hours at200° C. The mixture was then cooled to room temperature, the autoclavewas depressurized, and the resultant partially and completelyfluorinated benzotrifluorides were removed from the reaction mixture bydistillation. The resultant distillate was analyzed by gaschromatography. The results can be seen in Table 1.Tetrafluorobenzotrifluoride was obtained in purified form from thedistillate by fractional distillation.

Example 6 Inventive Preparation of Tetrafluorobenzotrifluoride

The procedure of Example 5(a) was followed, but the catalyst was 6.6 gof N-(N,N-dimethylimidazolidino)tris(diethylamino)-phosphazeniumchloride and, instead of dichloromethane, 28 g of sulfolane were used.In addition, in substep (b) the mixture was only heated for 24 hours at200° C. The analytical results after carrying out steps (a) and (b) canbe seen in Table 1.

Example 7 Inventive Preparation of Tetrafluorobenzotrifluoride

The procedure of Example 5(a) was employed, but the catalyst was 8.24 gof diethylaminobis(tetramethylguanidino)sulfonium bromide, and in step(b) the mixture was heated for only 24 hours at 200° C. The analyticalresults obtained after carrying out substeps (a) and (b) can be seen inTable 1.

Comparison Example 6 Preparation of TetrafluorobenzotrifluorideAccording to the Prior Art

The procedure of Example 5(a) was followed, but the catalyst was 8.38 gof tetraphenylphosphonium bromide, and in substep (a) the mixture washeated for 28 hours at 200° C. The analytical results obtained aftercarrying out substeps (a) and (b) can be seen in Table 1.

TABLE 1 Contents of halogenated benzotrifluorides (BTF), figures in %Tetra- Trichloro- Dichloro- Monochloro- Tetra- chloro- monofluoro-difluoro- trifluoro- fluoro BTF BTF BTF BTF BTF after substep (a)Example 5 0 21 66 0 0 Example 6 0 5 70 24 1 Example 7 4 51 44 1 0Comparative 19 62 19 0 0 Example 6 after substep (b) Example 5 0 0 0 1784 Example 6 0 0 0 33 67 Example 7 0 0 0 35 65 Comparative 0 14 78 6 1Example 6

Example 8 Inventive Preparation ofN-(N,N-dimethylimidazolidino)tris(diethylamino-phosphonium) chloride,Formula (VI)

282.9 g of phosphorus pentachloride in 1000 ml of dichloromethane wereplaced under an inert gas atmosphere in a 4 liter 3-neck flask equippedwith anchor stirrer, dropping funnel, and gas inlet tube and 730 g ofdiethylamine were added in portions at −30° C. Appropriate coolingensured that the temperature did not exceed −15° C. After addition wascomplete, the reaction mixture was allowed to warm up to roomtemperature and was then stirred for a further 2 hours. Then, at 0° C.,30 g of ammonia were introduced, and the mixture was again allowed towarm up to room temperature and was further stirred for 2 hours at roomtemperature. All volatile constituents of the reaction mixture were thentaken off in vacuo and the residue was dissolved in a mixture of 350 mlof water and 550 g of 40% strength by weight of aqueous sodium hydroxidesolution. After the mixture was stirred for one hour at roomtemperature, ammonia, diethylamine, and water were separated bydistillation and a residue was obtained that essentially comprised(ethyl₂N)₃P—NH₂ ⁺Cl⁻ and sodium chloride. 2800 ml of 50% strength byweight aqueous sodium hydroxide solution were added and extraction withtoluene produced (ethyl₂N)₃P═NH in 85% yield.

This material (131 g) was added in portions at −10 to −20° C. to asolution of 42.2 g of 2-chloro-1,3-dimethylimidazolinium chloride in 250ml of dichloromethane. The mixture was then stirred for 4 hours at 0° C.and for 2 hours at room temperature. The solvent was then removed invacuo, the residue was suspended in 300 ml of methanol, and 18.4 g ofpotassium methoxide dissolved in 100 ml of methanol were added at −20°C. The reaction mixture was allowed to warm to room temperature and wasfiltered and the solvent was taken off from the filtrate. This producedN-(N,N-dimethylimidazolidino)tris(diethylaminophosphonium) chloride in93% purity.

Melting point: 64 to 65° C.

-   ¹H-NMR (200 MHz, CDCl₃): δ=0.69 (t, ³J_(H-H)=6.9H, 18H, CH₃CH₂N),    2.49 (s, 6H, CH₃N), 2.65 (dq, ³J_(H-H)=6.9 Hz, ³J_(H-H)=10.7 Hz,    12H, CH₂CH₂)-   ³¹P-NMR (80 MHz, decoupled): δ=19.1 (s)-   ¹³C-NMR (50.3 MHz, CDCl₃): δ=13.2 (s, CH₃, CH₃CH₂N), 33.3 (s, CH₃,    CH₃N), 39.4 (s, CH₃, CH₃CH₂N), 47.3 (s, CH₂, CH₂CH₂),155.6 (d, C═N,    ²J_(C-P)=25.1 Hz)

Example 9 Inventive Preparation ofDiethylaminobis(tetramethylguanidino)sulfonium Bromide, Formula (VII)

Under an inert gas atmosphere, 7.5 g of bromine were added dropwise at−35° C. to a solution of 8.85 g of bis(diethylamino) sulfide in 40 ml ofdichloromethane. After the addition the mixture was further stirred for30 minutes at −35° C. and then 11.5 g of tetramethylguanidine were addeddropwise. The mixture was allowed to warm to room temperature, furtherstirred for 1 hour, and then cooled to 0° C. At this temperature, 2.8 gof sodium ethoxide (dissolved in 50 ml of methanol) were added and themixture was then allowed to come to room temperature. Methanol was takenoff in vacuo at 20 to 100° C. and the residue was washed with pentane.This produced 17.6 g of a 4:1 mixture ofdiethylaminobis(tetramethylguanidino)sulfonium bromide withbisdiethylamino(tetramethyl-guanidino)sulfonium bromide.Recrystallization from acetone/diethyl ether produced 8.5 g (41.3% oftheory) of diethylaminobis(tetramethyl-guanidino)sulfonium bromide inpure form.

Melting point: 117 to 119° C.

-   ¹³C-NMR (50.3 MHz, CDCl₃): δ=14.5 (CH₃, CH₃CH₂N), 41.1 (CH₃, CH₃N)    41.7 (CH₂, CH₃CH₂N).

Example 10 Inventive Preparation of Tris(tetramethylguanidino)sulfoniumChloride

10 g of sulfur dichloride in 100 ml of dichloromethane were introducedunder an inert gas atmosphere at −78° C. and 3.4 g of chlorine gas werecondensed into the mixture. 69.0 g of tetramethylguanidine were thenadded and the mixture was allowed to warm up slowly to room temperature.The solvent was removed in vacuo and the residue was cooled to 0° C. Atthis temperature, 5.8 g of sodium methoxide dissolved in 40 ml ofmethanol were added and the mixture was then allowed to warm up to roomtemperature. The methanol was taken off in vacuo. This producedtris(tetramethylguanidino)sulfonium chloride in 97% yield and 96.5%purity.

Melting point: 115 to 1 16° C.

-   ¹H-NMR (200 MHz, CDCl₃): δ=2.83 (s, 18H, CH₃N)-   ¹³C-NMR (50.3 MHz, CDCl₃): δ=40.9 (CH₃, CH₃N), 165.0 (C═N)

Example 11 Inventive Preparation ofDiethylaminobis[tris(diethylamino)phosphazenyl]-sulfonium Bromide,Formula VII)

5.0 g of bromine were added dropwise under an inert gas atmosphere at−35° C. to a solution of 5.7 g of bisdiethylamino sulfide in 25 ml ofdichloromethane. After addition was completed, the mixture was furtherstirred for 30 minutes at this temperature and 7.2 g oftris(diethyl-amino)phosphazene were then added. The mixture was allowedto warm to room temperature and was stirred for a further one hour andthen cooled to 0° C. again. At this temperature, 1.8 g of sodiummethoxide dissolved in 40 ml of methanol were added and the mixture wasthen allowed to warm up to room temperature. The methanol was taken offin vacuo and the residue was washed twice with pentane. This produced a4:1 mixture of diethylaminobis[tris(diethylamino)phosphazenyl]-sulfoniumbromide with bis(dimethylamino)trisdiethylamino)phosphazenylsulfoniumbromide.

-   ³¹P-NMR (80 MHz, decoupled): 38.4 (s, 20%), 32.7 (s, 80%)

1. A compound of the formula (I)

where A is a radical of the formula (II) or (III)

and B independently of A is a radical of the formula (IV) or (IVa)

or—S(NR¹R¹)₂  (IVa), where the individual R¹ are identical or differentand are each an unbranched or branched C₁–C₁₀ alkyl, unbranched orbranched C₂–C₁₀ alkylene, or C₆–C₁₂ aryl where one or more NR¹R¹ groupsare optionally also a 3- to 7-membered, saturated or unsaturated ringthat is formed from one nitrogen atom, the remainder of the ring atomsbeing carton atoms, where the radical of the formula (II) and the

 group in formula (IV) can also be the radical of a saturated orunsaturated 4- to 8-membered ring that contains two nitrogen atoms, theremainder of the ring atoms being carbon atoms, X is nitrogen orphosphorus, and An^(⊖) is one equivalent of an anion.
 2. A compositioncomprising a compound of the formula: